Browsing by Author "Grassie, Michael"

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    Investigating the phosphorylation of ser695/thr696 and ser852/thr853 regions of smooth muscle myosin phosphatase targeting subunit
    (2012) Grassie, Michael; MacDonald, Justin A.
    MYPTl has proven to be a key regulator in smooth muscle contraction and relaxation through the mechanisms of Ca2+ sensitization and desensitization. The regulation of MYPTl is controlled through the phosphorylation of several key residues. Kinase assays were carried out to confirm which amino acid residues of MYPT 1 were targeted by PKA and PKG in vitro. The following residues were then examined for functional significance in vitro and in situ with the use of recombinant proteins and RT A smooth muscle. From our studies we demonstrate the first direct evidence of in situ dual phosphorylation of MYPTl at Ser695/Thr696 and Ser852/Thr853. Also, that pre­phosphorylation of Ser852 by PKA/PKG has an inhibitory effect on the ability of ROK to phosphorylate the neighboring inhibitory residue of Thr853, similar to the effect previously observed for the Ser695/Thr696 region. Furthermore, the pre-phosphorylation ofThr696 by ROK decreased the ability of PKA/PKG to phosphorylate Ser695 in vitro and in situ.